【摘要】 针对薄膜型隔声超材料,在考虑内嵌质量块的形状和尺寸的前提下,研究其隔声降噪机理及隔声性能的微结构参数影响规律。首先建立薄膜型隔声超材料多自由度的振动分析模型,该模型引入内嵌的圆盘形质量块的平移和绕面内轴旋转自由度的模态特性。进而研究薄膜型超材料单胞结构单元的弹性常数、质量块质量及尺寸等参数对薄膜型超材料隔声"带隙"频段的影响。研究结果表明:金属圆盘形质量块的质量、半径以及橡胶薄膜的弹性常数对薄膜型超材料的固有振动频率均产生一定的影响;质量块半径越大,低频段的"带隙"的频率将向高处移位;质量块的质量越小,系统低频和高频段的"带隙"频率均增大,但此时中频段的"带隙"频率在166 Hz附近基本保持稳定;薄膜弹性常数的增大将导致中频段"带隙"频率增大,但影响不显著。更多还原

【Abstract】 Membrane-type acoustic metamaterials have demonstrated unusual capacity in controlling low-frequency sound transmission/reflection. First,an analytical vibroacoustic membrane model is developed in this work to study the band gap movement behavior of sound insulation of the metamaterial. The membrane-type acoustic metamaterial is composed of a prestretched elastic membrane attached a rigid disc-shaped mass. Especially,in the model effects of in-plane axis rotation and the translation freedom of the disc-shaped mass block were respectively introduced.Secondly,the effects of elastic constant of structural unit,and the influence of both quality value and radius size of the disc-shaped mass in this type of vibration absorbing material on the band-gaps movement behavior of low frequency and/or high frequency region were comprehensively explored. The results indicated that the band-gap and its movement feature are effected by quality and radius size of metal disc-shaped mass and also by the elastic property of rubber film material. The larger the radius of the disc mass,the frequency of the low frequency band of " band gap" will shift to higher range. The " band gap frequency" of the system low frequency and high frequency region also obviously increases with mass quality decrease. Meanwhile,with mass changes,the " band-gap" frequency of the middle band is close to the fixed value near 166 Hz. The increase of rubber film elastic coefficient will lead to an increase in the frequency of the " band-gap" of medium frequency band,but this effect is not significant.更多还原